Evaluation of the tribological properties of DLC for engine applications

S. D.A. Lawes, M. E. Fitzpatrick, S. V. Hainsworth

Research output: Contribution to journalArticle

29 Citations (Scopus)

Abstract

Diamond-like carbon (DLC) coatings are used in automotive engines for decreasing friction and increasing durability. There are many variants of DLC films which provide a wide range of mechanical, physical and tribological properties. The films can be extremely hard (>90 GPa), give low coefficients of friction against a number of counterfaces and exhibit low wear coefficients. The films are often considered to be chemically inert. The properties of DLC films depend to a large degree on the relative proportions of graphitically- (sp2) and diamond-like (sp3)-bonded carbon but the inclusion of elements such as hydrogen, nitrogen, silicon, tungsten, titanium, fluorine and sulphur can dramatically change their tribological response. Two different types of DLC, a WC/C amorphous hydrogenated DLC (WC/C a-C : H) coating and an amorphous hydrogenated DLC (a-C : H) have been investigated. The mechanical and tribological properties have been evaluated by nanoindentation, scratch and wear testing and friction testing in an instrumented cam-tappet testing rig. The deformation mechanisms and wear processes have been evaluated by scanning electron and atomic force microscopy. The results show that the harder a-C : H film was more wear resistant than the softer WC/C a-C : H film and performed better in the cam-tappet testing rig.

Original languageEnglish
Article numberS03
Pages (from-to)5427-5437
Number of pages11
JournalJournal of Physics D: Applied Physics
Volume40
Issue number18
DOIs
Publication statusPublished - 30 Aug 2007
Externally publishedYes

Fingerprint

Diamond
engines
Diamonds
Carbon
diamonds
Engines
Wear of materials
evaluation
carbon
Diamond like carbon films
Cams
Testing
Friction
cams
Coatings
Tungsten
Fluorine
friction
Silicon
Nanoindentation

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Acoustics and Ultrasonics
  • Surfaces, Coatings and Films

Cite this

Evaluation of the tribological properties of DLC for engine applications. / Lawes, S. D.A.; Fitzpatrick, M. E.; Hainsworth, S. V.

In: Journal of Physics D: Applied Physics, Vol. 40, No. 18, S03, 30.08.2007, p. 5427-5437.

Research output: Contribution to journalArticle

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